What happened
On 23 May 2022, a DJI Matrice 300 RTK remotely piloted aircraft, registered ZT-XNU, was conducting an aerial survey at the Black Rock Manganese Mine in Hotazel, Northern Cape. The flight was being operated under visual line of sight conditions as part of an aerial survey mission.
After ascending to approximately 240 metres above ground level, the aircraft experienced a sudden malfunction roughly nine minutes into the flight. The pilot observed multiple electronic speed control (ESC) error messages on the controller screen. Following these errors, the aircraft ceased responding to pilot commands and entered an uncontrolled descent, eventually impacting the rocky terrain within the mine area. The impact resulted in substantial damage to the aircraft, though no injuries to people on the ground were reported.
The investigation
SACAA AIID investigators reviewed flight log data retrieved from the DJI controller to reconstruct the sequence of events. The logs indicated that at approximately eight minutes and 59 seconds of flight time, the aircraft's airframe detected a side shock while operating at an altitude of nearly 240 metres. This impact was immediately followed by a sharp, uncontrolled roll to the left and the subsequent appearance of ESC errors.
While the operator's technical report noted that power levels and signal strength remained stable prior to the malfunction, the flight logs strongly suggested an external physical impact. Investigators noted that the aircraft was disposed of by the operator before photographic evidence of the airframe could be captured, as the operator initially believed the event was not reportable.
Findings
- The flight was conducted in clear weather conditions with no significant wind or visibility issues.
- The pilot held a valid Remote Pilot Licence and medical certificate.
- The aircraft had undergone a maintenance inspection approximately six hours prior to the accident.
- A possible bird strike caused the aircraft to lose stability and enter a terminal descent.